1. Technical Field
A method for forming patterns in a semiconductor device is disclosed, and more particularly, a method for forming patterns in a semiconductor device is disclosed which can increase the contact area between the photoresist and the anti-reflective film by performing an etching process on the anti-reflective film during the process of forming a photoresist pattern so as to form fine irregularities, thereby preventing the collapse of a photoresist pattern.
2. Description of the Related Art
It is known from conventional microfine pattern-forming processes that diffracted light and reflective light emitted from the lower film result in standing waves generated by optical properties of the lower film layer. As a result, variation in the thickness of a photoresist film, reflective notching, and/or variations of the critical dimension (hereinafter referring to as “CD”) of the photoresist pattern unavoidably occur.
Accordingly, a protecting layer for maintaining the reflection on the lower film layer between the lower film and the photoresist has been introduced. The protecting layer is fabricated from materials with excellent light-absorbing ability within wavelength ranges of exposure light sources, the protecting layer is typically referred to as an anti-reflective film.
Anti-reflective films may be generally classified into inorganic or organic-based anti-reflective film, dependent on the type of materials to be used. In recent years, the organic anti-reflective films have been widely used and so, several organic anti-reflective films have been developed.
Meanwhile, when the adhesion between the photoresist and the organic anti-reflective film is poor, the photoresist pattern formed on the upper portion of the anti-reflective film may collapse. To solve such a problem, two techniques are mainly used. First, in order to increase the adhesion between the photoresist and the anti-reflective film, the organic anti-reflective film is developed so it conforms to the specific photoresist used in the formation of a pattern. However, the development of the organic anti-reflective film is time consuming and therefore costly.
Secondly, a method for increasing the contact area between the photoresist pattern and the anti-reflective film may be employed to increase the adhesion between the photoresist and the anti-reflective film. However, once the CD of the pattern is determined, the contact area between the anti-reflective film and the photoresist pattern is, for all practical purposes, fixed. Thus, conventionally, no method has been developed for effectively increasing the contact area between the anti-reflective film and the photoresist pattern.
Hence, in case of forming a photoresist pattern according to the conventional art, there still remains the phenomenon of the collapse of the pattern.
Due to such problems of the conventional art, there is an urgent need for a method for forming patterns of a semiconductor device which can prevent the collapse of the pattern by effectively increasing the contact area between the photoresist pattern and the anti-reflective film, and thus increasing adhesion between the pattern and the anti-reflective film.